Mathematics · Time and Work

Rahul and Sohan have respective completion times of 15 and 25 days for a task. They began working together on the project, but after a few days, Rahul left and Priya, who can finish the entire task on her own in 12 days, joined. Three days before the job was finished, Priya left. Determine the fraction of work completed by Sohan if Rahul and Priya worked for an equal number of days.